Comparison · Minerals
Cryolite vs Heulandite
Cryolite and Heulandite are easy to confuse because both are minerals. Heulandite is harder (Mohs 3.5–4) than Cryolite (Mohs 2.5–3), so Heulandite will scratch Cryolite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Cryolite and Heulandite
- Heulandite is harder (Mohs 3.5–4) than Cryolite (Mohs 2.5–3), so Heulandite will scratch Cryolite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
- Cryolite feels noticeably heavier for its size (specific gravity 2.95–3.0 versus 2.1–2.2 for Heulandite).
- They overlap in clear, brown, and red, but Heulandite also comes in pink and yellow.
Cryolite vs Heulandite properties
| Property | Cryolite | Heulandite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 2.5–3 | 3.5–4 |
| Luster | Vitreous to greasy or pearly | Vitreous, pearly on cleavage |
| Streak | White | White |
| Transparency | Transparent to translucent | Transparent to translucent |
| Specific gravity | 2.95–3.0 | 2.1–2.2 |
| Crystal system | Monoclinic | Monoclinic |
| Common colors | Colorless, White, Brownish, Reddish | White, Colorless, Pink, Red, Brown, Yellow |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Cryolite and Heulandite trade in a similar range, around $20.
About Cryolite
Cryolite is a rare sodium aluminum fluoride mineral, Na3AlF6, historically significant as a flux in the industrial extraction of aluminum metal from bauxite ore. It is best known from a single massive deposit at Ivigtut, Greenland, which was, until its exhaustion, essentially the only commercially significant source on Earth. Its name comes from the Greek for "ice stone," reflecting its unusual property of becoming nearly invisible when submerged in water due to a refractive index close to that of water itself.
About Heulandite
Heulandite is a calcium- and sodium-bearing zeolite mineral, part of a group known for its coffin-shaped monoclinic crystals with a distinctive pearly luster on one prominent cleavage face. It typically forms as a secondary mineral filling vesicles and fractures in basaltic and volcanic rocks, alongside other zeolites deposited by cooling hydrothermal fluids. Heulandite is named after English mineral collector Henry Heuland, whose collection contributed significantly to early zeolite mineralogy.
Cryolite vs Heulandite FAQ
Is Cryolite the same as Heulandite?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Heulandite is harder (Mohs 3.5–4) than Cryolite (Mohs 2.5–3), so Heulandite will scratch Cryolite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
How can you tell Cryolite from Heulandite?
Heulandite is harder (Mohs 3.5–4) than Cryolite (Mohs 2.5–3), so Heulandite will scratch Cryolite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Cryolite feels noticeably heavier for its size (specific gravity 2.95–3.0 versus 2.1–2.2 for Heulandite). They overlap in clear, brown, and red, but Heulandite also comes in pink and yellow.
Which is harder, Cryolite or Heulandite?
Heulandite is harder: Mohs 3.5–4 against Mohs 2.5–3 for Cryolite.
Which is more valuable, Cryolite or Heulandite?
Typical specimens of Cryolite and Heulandite trade in a similar range, around $20.
